海南橡胶林下种植长裙竹荪连作障碍分析

Analysis on Continuous Cropping Obstacles of Dicyophora indusiata under RubberForest in Hainan

摘要: 为探究海南橡胶林下种植长裙竹荪连作障碍的原因，应用微生物纯培养技术和BIOLOG-ECO微平板等方法对不同连作年限的长裙竹荪覆土层土壤可培养微生物、功能微生物、微生物群落功能多样性、土壤理化性质和酶活性进行分析。结果显示，随着长裙竹荪连作年限的增加，土壤pH减少，有机质和全钾含量显著降低，全氮和全磷含量显著升高；土壤中可培养微生物总数和固氮菌、好氧纤维素分解菌、亚硝化细菌以及反硝化细菌4种功能微生物数量先升高后减少，并且均在连作第一年达到峰值，整体呈现从“细菌性”向“真菌性”转变的趋势；土壤蔗糖酶活性先降低后升高，脲酶和脱氢酶活性则先升高后降低；不同连作年限下的长裙竹荪土壤微生物的AWCD值不同，对不同碳源的利用程度和利用特征也不同，土壤微生物群落的Shannnon指数、Simpson指数和Pielou指数差异不显著，连作第一年的土壤微生物群落的McIntosh指数显著最低。综上所述，橡胶林下连作长裙竹荪影响土壤理化性质和土壤酶活性，长裙竹荪“自溶”产生的“毒副”物质的积累影响土壤中可培养微生物和功能微生物的数量和功能，同时影响土壤微生物群落功能特征。由此可见，土壤“微环境”的变化可能是造成橡胶林下长裙竹荪连作障碍的主要原因。因此，为提高橡胶林下连作长裙竹荪的产量和品质，有效调节连作土壤的质量，提供适宜的林下环境条件尤为重要。

Abstract: In order to explore the reasons for continuous cropping obstacles of Dictyophora indusiata under rubber forest in Hainan province, pure microbial culture technology and BIOLO-ECO microplate were used to analyze the culturable microorganisms, functional microorganisms, functional diversity of microbial communities, physical and chemical properties of soil and enzyme activities in the soil covered by Dictyophora indusiata for different continuous cropping years. The results showed that with the increase of continuous cropping years, soil pH decreased, organic matter and total potassium content decreased significantly, and total nitrogen and total phosphorus content increased significantly; The total number of culturable microorganisms and the number of nitrogen fixing bacteria, aerobic cellulose decomposing bacteria, nitrite bacteria and denitrifying bacteria in the soil increased first and then decreased, reaching the peak in the first year of continuous cropping, showing a trend of transformation from “bacterial” to “fungal” as a whole. Soil sucrose activity decreased first and then increased, while urease and dehydrogenase activity increased first and then decreased. The AWCD values of soil microorganisms of Dictyophora indusiata under different continuous cropping years were different, and the utilization degree and characteristics of different carbon sources were different. The Shannon index, Simpson index and Pielou index of soil microbial community were not significantly different, and the McIntosh index of soil microbial community in the first year of continuous cropping was significantly lowest. To sum up, the continuous cropping of Dictyophora indusiata under rubber forest affects the physical and chemical properties of the soil and the activity of soil enzyme, and the accumulation of “toxic and by-product” substances produced by the “autolysis” of Dictyophora indusiata affects the number and function of culturable microorganisms and functional microorganisms in the soil, as well as the functional characteristics of the soil microbial community. It can be seen that the change of soil “Micro-environment” may be the main reason for the continuous cropping obstacle of Dictyophora indusiata under rubber forest. Therefore, in order to improve the yield and quality of the continuous cropping Dictyophora indusiata under rubber forest, effectively regulate the quality of continuous cropping soil, it is particularly important to provide suitable understory environmental conditions.